Control of an outbreak of salmonellosis caused by drug-resistant Salmonella anatum in horses at a veterinary hospital and measures to prevent future infections.

Salmonella anatum was isolated from horses treated at a private veterinary clinic or at a university veterinary medical teaching hospital. All isolates were resistant to most commonly used antibiotics. Because of the severity of disease resulting from outbreaks of infections with drug-resistant strains of S anatum, an epidemiologic investigation was conducted. Enteric bacteria, including S anatum, that were resistant to most antibiotics were isolated from the private veterinary clinic environment. Salmonella anatum was not isolated from the university teaching hospital environment. To prevent transmission, disinfection and isolation protocols were reviewed, and changes were implemented, including discontinuing use of power sprayers for cleaning, improving a two-step disinfection process, restricting movement of horses, and enhancing awareness of Salmonella spp transmission. Communication and prompt action are pivotal in preventing dissemination of resistant strains of Salmonella spp in a clinic or hospital environment.